Roller mill



P. R. v. KNUPFFER ROLLER MILL Dec. 13,; 1932 Filed DGO. 11, 1929 Il l//IIII lllllllllllllll v Patented Dec. 13, 1932" UNITED STATES :PAUL n. v. KN'PFFER, or BERLIN-FRIEDENAU, GERMANY' ROLLER MILL Application led December 11, 1929, Serial No. 413,362, and in Germany December 14, 1928.

heretofore rigid rolls have always been employed. With two coacting rolls one roll has been yieldingly journalled in order to lenable it to give to a definite extent, for preventing the journals of the rolls being fractured or subjected to too great stresses during the passage of too hard or large pieces. Owing to the give of the yieldingly journalled roll the grinding action is interfered with over the entire length of the roll, even when the actual obstacle amounts to only a small fraction of the length of the roll, so

'that a large quantity of unground material may pass between the rolls. The mounting of yielding bearings for the yielding rolls on the outside of the mill housing provides some diriculty, is costly and has the additional disadvantage that the bearing has to be sealed towards the inside of the mill housing and that such a seal can' never be kept so tight as to prevent dust getting into the place in which the roller mills are working.

IAll these disadvantages are overcome by the present invention through on@ more rolls of the roller mill being itself or themselves made elastic (yielding) so as no longer to require special yielding bearings. The rolls consist of a bar of steel or some other suitable material, of square, rectangular, round or elliptical cross-section, which is wound so as to form a cylindrical conical or double-conical, helical spring.

Ashelical springs can be made suiciently stili such a mill may be used for grinding hird material such as coal, pigments and the e. yThe mill has the further advantage that the material to be ground can be dried in the mill itself at high temperatures and a high -'press-ure in the interior of the mill as there are no. bearings inside the mill which are sensitive to high temperatures and have to be v lubricated and the elastic rolls require no Aexternal `bearings and therefore do not re,-

qnireisealing with respect to the housing.

In the accompanying drawing several constructional examples of the invention are' shown by ,way of example.

Fig. 1 shows an elastic roll in side and end elevati-on comprised of a single thread cylindrical helical spring. l

Fig. 2 shows another form of elastic roll in side and end elevation, comprised of a multiple thread cylindrical spring.

Fig. 3 shows a cross section of a roller mill having one rigid roll and two elastic rolls.

Fig. 4 shows a cross section of a roller mill in which the stressing of the elastic roll is effected by means of two rigid rolls.

Fig. 5 shows in sectional elevation a roller mill in which the stressing of the elastic rolls bers mounted on the casing of the mill.

Fig. 6 shows a cross section along the line VI-VI of Fig. 5.

Fig. 7 shows an arrangement of rolls in which the stressing of the elastic roll is effected by means of a smooth rigid roller and a rigid roller provided with a thread-like projection having convolutions which correspond to those in the elastic'roll but which wind in a direction contrary to the convolutions of the elastic roll. E

Fig. 8 shows by way of example the construction of a rigid roll provided with surface convolutions for use `in the arrangement of rolls shown in Fig. 7. J

Fig. 9 shows an elastic roll according to the invention in which agap is left between the individual convolutions.

Fig. l0 shows in elevation an elastic roll which is conical in shape.

V,is ele'cted by means of wedge-shaped mem- Fig. 11 shows in elevation an elastic roll according to the invention which is of double-cone shape.

Figs. 1 and 2 show iront and end elevations of elastic rolls according to the inven-` tion which are constructed in the manner of lsingle or multiple thread cylindrical helicylindricall shape. `The roll shown in Fig. 2

is comprised of a multiple thread icylindrical spring, in this case a triple thread spring. The roller shown is made by intermeshing three cylindrical helical springs, 21, 21" and 21".

If required the elastic rolls may be wound so as to form conical or double-conical helical springs, as shown in elevation in Figs. 10 and 11, the former gure showing a roll comf prised of a conical-wound helical spring 22, and the latter figure showing a helical spring 23 wound in the form of a double cone.

Fig. 3 shows the cross-section of a roller mill with one rigid roll 1 and two elastic rolls 2. On an obstacle 3 passing between the two rolls land 2 the whole of the effective roll is not lifted off as hitherto but that part of the roll 2 where the obstacle is situated yields, while the remainder of the roll 2 remains in contact with the rigid roll l, thus preventing any interruption in the grinding operation. Y

Owing to the nature of the elastic roll it is necessary for it to have a certain initial amount of stressing with respect to the rigid driven roll. -This initial lstressing may be brought about in various different ways. Thus, by way of example, Fig. 4 shows a section of a mill in which the stressing of the elastic roll comprised of the cylindrical helical spring 24 is effected by a rigid counter roll 4 which may be yieldingly journalled with respect to the first rigid roll 31. When two or more elastic rolls are used, as shown in Fig. 3, the stressing may be effected by the mill housing itself.

As a further example, Figs. 5 and 6 show sections of a roller mill in which the initial stressing is produced by means of segmentshaped wedges 5 which are mounted on the inside of the wall of the mill housing 6 and are adjustable from the outside. The wedges 5 are separated from one another by slightly lower intermediate pieces 7 (Fig. 6), the arrangement being such that the edges of the wedges 5 form cutting edges with respect to the edges of the cylindrical helical springs of the elastic roll 2 which roll obliquely over them, the cutting edges having a shearing action at the place of contact and cutting up the material to be ground.

This cutting action of the edges of the cylindrical helical springs may also be produced at the place of contact with the drivin roll in accordance with Fig. 7, by the driving roll 51 being provided with helical grooves which are opposite handed to the convolutions of the elastic roll 25, a smooth, rigid roll 41 co-operating with the roll 51 to produce the requisite stress. Fig. 8 shows a constructional form of the roll 51 in Fig. 7. A cylindrical helical spring 8 is pushed over the smooth rigid roll 61, the convolutions of which spring are opposite handed to those of the elastic roll intended to co-operate with the rigid roll 61.

. 1n Order that the material being ound -cnn ,tricklefreely through the elastigc1` rolls the helical springs of the elastic roll are preferably wound as shown in Fig. 9 in such a manner that between the convolutions of the helical spring 26 suiiciently large gaps 9 are left which at the same time increase the shearing action of the edges of the helical spring. This shearing action of the edges of the elastic rolls may also be produced at the place of contact with the inside of the wall of the mill housing by the latter being provided, as shown in Fig. 3, with grooves or recesses 1l which extend over the entire length. The grooves have the further advantage that the sifting air will have freer access to the material being ground. Similar grooves 111 may be provided in the mill, shown in Fig. 4.

In the case of roller mills having two or more elastic rolls these rolls may in accord ance with Figs. 5 and 6 be journalled to the left and right in cages 10 in order to ensure that the rolls shall be at a uniform distance from one another.

What I claim is:

1. A roller mill for crushing materials of all kinds, comprising in combination a housing, a non-elastic roll and an elastic roll rotatable in said housing and in operative contact with one another, said elastic roll being supported solely at the periphery, and means on said housing operatively connected to the elastic roll for` producing an initial stress in the said elastic roll, as and for the purposes set forth.

2. A roller mill for crushing materials of all kinds, comprising in combination a housing, a non-elastic roll and an elastic roll rotatable in said housing and in operative contact with one another,l segment-shaped longitudinal wedges arranged around the inside of the wall of the housing so as to bear against the elastic roll for producing an initial stress in the elastic roll, separating pieces intermediate said wedges inside the housing for separating the wedges from one another and means operatively connected to the wedges and passed through the housing for adjusting the wedges from the outside.

3. A roller mill for crushing materials of all kinds, comprising in combination a housing, a non-elastic roll and a plurality of' elastic rolls rotatable in said housing with said elastic rolls in operative contact with said non-elastic roll and with the inside of the wall of the housing, said elastic rolls comprising helical springs vand the inside of the in the driving roll, as and for the purposes set forth. 1 5. A roller mill for crushing materials of all kinds comprising in combination a housing, a driven roll Within said housing, and a plurality of rolls in operative contact with, and actuated by, said driven roll, at least one ofthe said actuated rolls having a resilient and yielding co-operating surface and l0 being externally supported solely at the periphery.

6. A roller mill for crushing materials of l all kindshcomprising in combination a hous.-

ing, a 'driven roll Within said housing, and a plurality of rolls in operative contact with, and actuated by, said driven roll, at least one of the said actuated rolls being elastic and yielding inv itself and being externally supported solely at the periphery and comprising a helical spring.

- 7. A roller mill for crushing materials of all kinds comprising in combination a housing, cage members in said housing, a rigidsurfaced roll in said housing, and a plurality of resilient-surfaced rolls mounted on said cage members at a uniform distance from one another and adapted to rotate in said housing in operative contact with the said rigid-surfaced roll. v

50 8. A roller mill for crushing materials of all kinds, comprising in combination a housing, a roll having a rigid peripheral surface and a plurality of rolls with resilient Lperipheral surfaces rotatable lin said housing with said resilient-surfaced rolls inoperative contact with said rigid-surfaced roll and cages arranged between the ends of the resilient-surfaced rolls for spacing the latter at a uniform distance apart.

In testimony whereof I have signed my name to this specification.

nPAUL R. v. KNPFFER. 

